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van den Elsen LJW, Rekima A, Lynn MA, Isnard C, Machado S, Divakara N, Patalwala D, Middleton A, Stevens N, Servant F, Burcelin R, Lynn DJ, Verhasselt V. Diet at birth is critical for healthy growth, independent of effects on the gut microbiota. MICROBIOME 2024; 12:139. [PMID: 39068488 PMCID: PMC11282663 DOI: 10.1186/s40168-024-01852-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 05/30/2024] [Indexed: 07/30/2024]
Abstract
BACKGROUND Colostrum is the first milk for a newborn. Its high content in microbiota shaping compounds and its intake at the time of gut microbiota seeding suggests colostrum may be critical in the establishment of a healthy microbiota. There is also accumulating evidence on the importance of the gut microbiota for healthy growth. Here, we aimed to investigate the contribution of colostrum, and colostrum-induced microbiota to growth promotion. Addressing this question is highly significant because (1) globally, less than half of the newborns are fully colostrum fed (2) the evidence for the importance of the microbiota for the prevention of undernutrition has only been demonstrated in juvenile or adult pre-clinical models while stunting already starts before weaning. RESULTS To address the importance of diet at birth in growth failure, we developed a unique mouse model in which neonates are breastfed by mothers at an advanced stage of lactation who no longer provide colostrum. Feeding newborn mice with mature milk instead of colostrum resulted in significant growth retardation associated with the biological features of chronic undernutrition, such as low leptin levels, dyslipidemia, systemic inflammation, and growth hormone resistance. We next investigated the role of colostrum in microbiota shaping. At the end of the lactation period, we found a major difference in gut microbiota alpha diversity, beta diversity, and taxa distribution in control and colostrum-deprived mice. To determine the causal relationship between changes in microbiota and growth trajectories, we repeated our experiment in germ-free mice. The beneficial effect of colostrum on growth remained in the absence of microbiota. CONCLUSION Our data suggest that colostrum may play an important role in the prevention of growth failure. They highlight that the interplay between neonatal gut microbiome assembly and diet may not be as crucial for growth control in the developing newborn as described in young adults. This opens a paradigm shift that will foster research for colostrum's bioactives that may exert a similar effect to microbiota-derived ligands in promoting growth and lead to new avenues of translational research for newborn-tailored prevention of stunting. Video Abstract.
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Affiliation(s)
- Lieke J W van den Elsen
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia.
- Telethon Kids Institute, Perth, WA, Australia.
| | - Akila Rekima
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth, WA, Australia
| | - Miriam A Lynn
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | | | - Savannah Machado
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth, WA, Australia
| | - Nivedithaa Divakara
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia
- Telethon Kids Institute, Perth, WA, Australia
| | - Diana Patalwala
- National Imaging Facility, Centre for Microscopy Characterisation and Analysis, University of Western Australia, Perth, WA, Australia
| | - Alana Middleton
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia
| | - Natalie Stevens
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | | | | | - David J Lynn
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | - Valerie Verhasselt
- Larsson-Rosenquist Centre for Immunology and Breastfeeding, School of Medicine, The University of Western Australia, Perth, WA, Australia.
- Telethon Kids Institute, Perth, WA, Australia.
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de Sousa Rebouças A, Costa Lemos da Silva AG, Freitas de Oliveira A, Thalia Pereira da Silva L, de Freitas Felgueiras V, Cruz MS, Silbiger VN, da Silva Ribeiro KD, Dimenstein R. Factors Associated with Increased Alpha-Tocopherol Content in Milk in Response to Maternal Supplementation with 800 IU of Vitamin E. Nutrients 2019; 11:nu11040900. [PMID: 31013594 PMCID: PMC6520676 DOI: 10.3390/nu11040900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/16/2022] Open
Abstract
Background: Vitamin E supplementation might represent an efficient strategy to increase the vitamin E content in milk. The present study aimed to evaluate the impact of supplementation with 800 IU RRR-alpha-tocopherol on the alpha-tocopherol content of milk and the factors associated with the increase in vitamin E. Methods: Randomized clinical trial with 79 lactating women from Brazil, who were assigned to the control group, or to the supplemented group (800 IU of RRR-alpha-tocopherol). Milk and serum were collected between 30 and 90 days after delivery (collection 1), and on the next day (collection 2). Alpha-tocopherol was analyzed using high-performance liquid chromatography. Results: In the supplemented group, the alpha-tocopherol content in serum and milk increased after supplementation (p < 0.001). In the multivariate analysis, only alpha-tocopherol in milk (collection 1) was associated with the level of this vitamin in milk after supplementation (β = 0.927, p < 0.001), and binary logistic regression showed that the dietary intake was the only determinant for the greater effect of supplementation in milk. Conclusion: The pre-existing vitamin level in milk and diet are determinants for the efficacy of supplementation in milk, suggesting that in populations with vitamin E deficiency, high-dose supplementation can be used to restore its level in milk.
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Affiliation(s)
- Amanda de Sousa Rebouças
- Department of Biochemistry, Federal University of Rio Grande do Norte, 59078-970 Natal-RN, Brazil.
| | | | | | | | | | - Marina Sampaio Cruz
- Department of Pharmacy, Federal University of Rio Grande do Norte, 59012-570 Natal-RN, Brazil.
| | | | | | - Roberto Dimenstein
- Department of Biochemistry, Federal University of Rio Grande do Norte, 59078-970 Natal-RN, Brazil.
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Li K, Jiang J, Xiao H, Wu K, Qi C, Sun J, Li D. Changes in the metabolite profile of breast milk over lactation stages and their relationship with dietary intake in Chinese women: HPLC-QTOFMS based metabolomic analysis. Food Funct 2019; 9:5189-5197. [PMID: 30259935 DOI: 10.1039/c8fo01005f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The aim of the present study was to comprehensively evaluate the changes in the metabolite profile of breast milk over lactation stages and their relationship with dietary intake in Chinese women by HPLC-QTOFMS based metabolomic analysis. The colostrum, transitional milk and mature milk of thirty healthy lactating women were collected for analysis. Eighty-four differential metabolites over lactation stages were identified, including 12 fatty acyls, 15 glycerolipids, 23 glycerophospholipids, 7 sphingolipids, 7 vitamins, 5 nucleotides-related metabolites, 2 amino acids, 1 amino acid derivate, 9 dipeptides, 1 steroid hormone, 1 energy-related metabolite and 1 amine. Partial least-squares regression analysis indicated that the metabolite profiles of the colostrum, transitional milk and mature milk have a strong relationship with dietary intake (R2 values were 0.92, 0.87 and 0.74, respectively). However, among the 84 differential metabolites over lactation stages, only two showed a strong relationship with dietary intake: 1,24,25-(OH)3 vitamin D3 was positively correlated with the dietary intake of meat and eggs, protein and fat; 11β-hydroxyprogesterone was negatively correlated with the dietary intake of fruit and carbohydrate. After adjusting for dietary intake, the variation trend of all the 84 differential metabolites over lactation stages remained unchanged. In conclusion, 84 differential metabolites in the breast milk of Chinese women over lactation stages were identified, and their variation trend was independent of dietary intake. These metabolites were partially different from those identified in previous metabolomic studies in the Western population. The present study is quite meaningful for understanding the variation of nutritional requirements in Chinese infants at different developmental stages and manufacturing optimal infant formulas for them.
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Affiliation(s)
- Kelei Li
- Institute of Nutrition and Health, Qingdao University, Qingdao, China.
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Lipoprotein Lipase (LPL) Polymorphism and the Risk of Coronary Artery Disease: A Meta-Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14010084. [PMID: 28275220 PMCID: PMC5295335 DOI: 10.3390/ijerph14010084] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 12/30/2016] [Accepted: 01/03/2017] [Indexed: 12/17/2022]
Abstract
Background: In recent years, the lipoprotein lipase (LPL) polymorphism has been extensively investigated as a potential risk factor for coronary artery disease (CAD). However, the results of these studies have been inconsistent. Therefore, we performed this meta-analysis to explore the association between LPL polymorphism and CAD risk. Methods: The literature was searched from electronic databases such as Embase, China Biological Medicine Database, PubMed, Knowledge Infrastructure, and China National Web of Science by the key words “coronary artery disease”, “lipoprotein lipase” and “polymorphism”. All of the studies included in this manuscript met the inclusion and exclusion criteria. An odds ratio (OR) analysis using a 95% confidence interval (CI) was employed to assess the association of the LPL polymorphism with CAD susceptibility. Results: We performed a meta-analysis of 14 case-control studies including HindIII, Ser447X and PvuII polymorphism. A statistically significant increase in the risk of CAD was associated with LPL HindIII polymorphism. This included HindIII H+H+ genotype (OR = 1.28, 95% CI = 1.09–1.49, p = 0.002, I2 = 43%) and H+ allele genotype (OR = 1.27, 95% CI = 1.03–1.58, p = 0.03, I2 = 67%). Ser447X XX genotype (OR = 2.37, 95% CI = 1.33–4.24, p = 0.004, I2 = 53%) was also associated with CAD risk. However, PvuII polymorphism was found to have no significant association with CAD risk. Conclusions: LPL HindIII polymorphism was significantly associated with the risk of CAD. For Ser447X polymorphism, it was found that only XX genotype was significantly associated with CAD risk. Furthermore, PvuII polymorphism had no significant association with CAD risk. It was considered that LPL HindIII polymorphism might serve as a potential biomarker for CAD risk.
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Allan CM, Larsson M, Jung RS, Ploug M, Bensadoun A, Beigneux AP, Fong LG, Young SG. Mobility of "HSPG-bound" LPL explains how LPL is able to reach GPIHBP1 on capillaries. J Lipid Res 2016; 58:216-225. [PMID: 27811232 DOI: 10.1194/jlr.m072520] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 10/31/2016] [Indexed: 12/22/2022] Open
Abstract
In mice lacking glycosylphosphatidylinositol-anchored high density lipoprotein binding protein 1 (GPIHBP1), the LPL secreted by adipocytes and myocytes remains bound to heparan sulfate proteoglycans (HSPGs) on all cells within tissues. That observation raises a perplexing issue: Why isn't the freshly secreted LPL in wild-type mice captured by the same HSPGs, thereby preventing LPL from reaching GPIHBP1 on capillaries? We hypothesized that LPL-HSPG interactions are transient, allowing the LPL to detach and move to GPIHBP1 on capillaries. Indeed, we found that LPL detaches from HSPGs on cultured cells and moves to: 1) soluble GPIHBP1 in the cell culture medium; 2) GPIHBP1-coated agarose beads; and 3) nearby GPIHBP1-expressing cells. Movement of HSPG-bound LPL to GPIHBP1 did not occur when GPIHBP1 contained a Ly6 domain missense mutation (W109S), but was almost normal when GPIHBP1's acidic domain was mutated. To test the mobility of HSPG-bound LPL in vivo, we injected GPIHBP1-coated agarose beads into the brown adipose tissue of GPIHBP1-deficient mice. LPL moved quickly from HSPGs on adipocytes to GPIHBP1-coated beads, thereby depleting LPL stores on the surface of adipocytes. We conclude that HSPG-bound LPL in the interstitial spaces of tissues is mobile, allowing the LPL to move to GPIHBP1 on endothelial cells.
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Affiliation(s)
- Christopher M Allan
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Mikael Larsson
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Rachel S Jung
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, DK-2200 Copenhagen N, Denmark and Biotech Research and Innovation Centre (BRIC), University of Copenhagen, DK-220 Copenhagen N, Denmark
| | - André Bensadoun
- Division of Nutritional Science, Cornell University, Ithaca, NY 14853
| | - Anne P Beigneux
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Loren G Fong
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Stephen G Young
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095 .,Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095
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Song S, Ge X, Cheng Y, Lu R, Zhang T, Yu B, Ji X, Qi Z, Rong Y, Yuan Y, Cheng Y. High-level expression of a novel recombinant human plasminogen activator (rhPA) in the milk of transgenic rabbits and its thrombolytic bioactivity in vitro. Mol Biol Rep 2016; 43:775-83. [PMID: 27230577 DOI: 10.1007/s11033-016-4020-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 05/21/2016] [Indexed: 12/19/2022]
Abstract
The human tissue-type plasminogen activator (tPA) is a key kinase of fibrinolysis that plays an important role in dissolving fibrin clots to promote thrombolysis. The recombinant human plasminogen activator (rhPA) has more thrombolytic advantages than the wild type tPA. To increase the half-life and thrombolytic activity of tPA, a mutant containing only the essential K2 fibrin-binding and P activating plasminogen domains of the wild type tPA was cloned. This fragment was then inserted into goat β-casein regulatory sequences. Then, a mammary gland-specific expression vector, PCL25/rhPA, was constructed, and the transgenic rabbits were generated. In this study, 18 live transgenic founders (12♀, 6♂) were generated using pronuclear microinjection. Six transgenic rabbits were obtained, and the expression levels of rhPA in the milk had a range of 15.2-630 µg/ml. A fibrin agarose plate assay of rhPA showed that it had strong thrombolytic bioactivity in vitro, and the highest specific activity was >360 (360 times more than that of alteplase). The results indicated that the rhPA containing only the K2 and P domains is efficiently expressed with higher thrombolytic bioactivity in the milk of transgenic rabbits. Our study also demonstrated a new method for the large-scale production of clinically relevant recombinant pharmaceutical proteins in the mammary glands of transgenic rabbits.
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Affiliation(s)
- Shaozheng Song
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Xin Ge
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Yaobin Cheng
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Rui Lu
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Ting Zhang
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Baoli Yu
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Xueqiao Ji
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Zhengqiang Qi
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Yao Rong
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Yuguo Yuan
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Yong Cheng
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China.
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Binder AK, Kosak JP, Janhardhan KS, Moser G, Eling TE, Korach KS. Expression of Human NSAID Activated Gene 1 in Mice Leads to Altered Mammary Gland Differentiation and Impaired Lactation. PLoS One 2016; 11:e0146518. [PMID: 26745373 PMCID: PMC4706436 DOI: 10.1371/journal.pone.0146518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/19/2015] [Indexed: 12/22/2022] Open
Abstract
Transgenic mice expressing human non-steroidal anti-inflammatory drug activated gene 1 (NAG-1) have less adipose tissue, improved insulin sensitivity, lower insulin levels and are resistant to dietary induced obesity. The hNAG-1 expressing mice are more metabolically active with a higher energy expenditure. This study investigates female reproduction in the hNAG-1 transgenic mice and finds the female mice are fertile but have reduced pup survival after birth. Examination of the mammary glands in these mice suggests that hNAG-1 expressing mice have altered mammary epithelial development during pregnancy, including reduced occupancy of the fat pad and increased apoptosis via TUNEL positive cells on lactation day 2. Pups nursing from hNAG-1 expressing dams have reduced milk spots compared to pups nursing from WT dams. When CD-1 pups were cross-fostered with hNAG-1 or WT dams; reduced milk volume was observed in pups nursing from hNAG-1 dams compared to pups nursing from WT dams in a lactation challenge study. Milk was isolated from WT and hNAG-1 dams, and the milk was found to have secreted NAG-1 protein (approximately 25 ng/mL) from hNAG-1 dams. The WT dams had no detectable hNAG-1 in the milk. A decrease in non-esterified free fatty acids in the milk of hNAG-1 dams was observed. Altered milk composition suggests that the pups were receiving inadequate nutrients during perinatal development. To examine this hypothesis serum was isolated from pups and clinical chemistry points were measured. Male and female pups nursing from hNAG-1 dams had reduced serum triglyceride concentrations. Microarray analysis revealed that genes involved in lipid metabolism are differentially expressed in hNAG-1 mammary glands. Furthermore, the expression of Cidea/CIDEA that has been shown to regulate milk lipid secretion in the mammary gland was reduced in hNAG-1 mammary glands. This study suggests that expression of hNAG-1 in mice leads to impaired lactation and reduces pup survival due to altered milk quality and quantity.
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Affiliation(s)
- April K. Binder
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Justin P. Kosak
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Kyathanahalli S. Janhardhan
- Integrated Laboratory Systems Incorporated, Research Triangle Park, North Carolina, United States of America
| | - Glenda Moser
- Integrated Laboratory Systems Incorporated, Research Triangle Park, North Carolina, United States of America
| | - Thomas E. Eling
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Kenneth S. Korach
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
- * E-mail:
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Wang Y, Sheng Z, Wang Y, Li Q, Gao Y, Wang Y, Dai Y, Liu G, Zhao Y, Li N. Transgenic Mouse Milk Expressing Human Bile Salt-Stimulated Lipase Improves the Survival and Growth Status of Premature Mice. Mol Biotechnol 2014; 57:287-97. [DOI: 10.1007/s12033-014-9822-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ontsouka EC, Albrecht C. Cholesterol transport and regulation in the mammary gland. J Mammary Gland Biol Neoplasia 2014; 19:43-58. [PMID: 24510467 DOI: 10.1007/s10911-014-9316-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 01/22/2014] [Indexed: 01/28/2023] Open
Abstract
The milk-producing alveolar epithelial cells secrete milk that remains after birth the principal source of nutrients for neonates. Milk secretion and composition are highly regulated processes via integrated actions of hormones and local factors which involve specific receptors and downstream signal transduction pathways. Overall milk composition is similar among mammalian species, although the content of individual constituents such as lipids may significantly differ from one species to another. The milk lipid fraction is essentially composed of triglycerides, which represent more than 95 % of the total lipids in human and commercialized bovine milk. Though sterols, including cholesterol, which is the major milk sterol, represent less than 0.5 % of the total milk lipid fraction, they are of key importance for several biological processes. Cholesterol is required for the formation of biological membranes especially in rapidly growing organisms, and for the synthesis of sterol-based compounds. Cholesterol found in milk originates predominantly from blood uptake and, to a certain extent, from local synthesis in the mammary tissue. The present review summarizes current knowledge on cellular mechanisms and regulatory processes determining intra- and transcellular cholesterol transport in the mammary gland. Cholesterol exchanges between the blood, the mammary alveolar cells and the milk, and the likely role of active cholesterol transporters in these processes are discussed. In this context, the hormonal regulation and signal transduction pathways promoting active cholesterol transport as well as potential regulatory crosstalks are highlighted.
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Affiliation(s)
- Edgar C Ontsouka
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, 3012, Bern, Switzerland
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Cheng Y, An LY, Yuan YG, Wang Y, Du FL, Yu BL, Zhang ZH, Huang YZ, Yang TJ. Hybrid expression cassettes consisting of a milk protein promoter and a cytomegalovirus enhancer significantly increase mammary-specific expression of human lactoferrin in transgenic mice. Mol Reprod Dev 2012; 79:573-85. [PMID: 22730016 DOI: 10.1002/mrd.22063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 06/08/2012] [Indexed: 11/06/2022]
Abstract
It is very important to develop an effective, specific, and robust expression cassette that ensures a high level of expression in the mammary glands. In this study, we designed and constructed a series of mammary gland-specific vectors containing a complex hybrid promoter/enhancer by utilizing promoter sequences from milk proteins (i.e., goat β-casein, bovine αs1-casein, or goat β-lactoglobulin) and cytomegalovirus enhancer sequences; vectors containing a single milk protein promoter served as controls. Chicken β-globin insulator sequences were also included in some of these vectors. The expression of constructs was analyzed through the generation of transgenic mice. Enzyme-linked immunosorbent assay (ELISA) analysis revealed that the hybrid promoter/enhancer could drive the expression of recombinant human lactoferrin (rhLF) cDNA at high levels (1.17-8.10 mg/ml) in the milk of transgenic mice, whereas control promoters achieved a very low rhLF expression (7-40 ng/ml). Moreover, the expression of rhLF was not detected in the serum or saliva of any transgenic animal. This result shows that all constructs, driven by the hybrid promoter/enhancer, had high mammary gland-specific expression pattern. Together, our results suggest that the use of a hybrid promoter/enhancer is a valuable alternative approach for increasing mammary-specific expression of recombinant hLF in a transgenic mouse model.
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Affiliation(s)
- Yong Cheng
- Engineering Research Centre for Transgenic Animal Pharmaceutics in Jiangsu Province, College of Veterinary Medicine, Yangzhou University, No. 12 Wenhui Rd., Yangzhou, Jiangsu, PR China.
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